Recent work in cognitive neuroscience reveals that, when one observes another person performing some action, neurons fire in one’s own motor cortex that are the very same neurons that would fire if one were also performing the observed action; these have been dubbed "mirror neurons". The principle of external or interpersonal isomorphism, formulated by the Gestalt psychologists, Köhler and Koffka, during the 1920’s through to the 1940’s, anticipated important aspects of the mirror neuron discovery. Moreover, both the Gestaltists’ theory, based on the principle of interpersonal isomorphism, and Gallese’s (2003) contemporary theory of "embodied simulation", inspired by the mirror neuron discovery, converge on the central claim that our general ability to understand another’s actions, emotions, and intentions, is implicit, automatic, and non-inferential.
Keywords: Interpersonal isomorphism, mirror neurons, Gestalt psychology, embodied simulation, embodied empathy.